This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We made prevascularized fibrin based tissue by coculture of Human Umbilical Vein Endothelial cells (HUVEC) and fibroblasts and implanted the prevascularized tissue into mice. We demonstrated that prevascularization accelerate the formation of functional anastomosis between the implanted tissue and host tissue. In order to make it clear how the vessels develop both in vitro and in vivo we will transduce the HUVECs and fibroblasts with red and green fluorescence protein respectively and image the in vitro and in vivo tissue with the Laser Scaning Microscope in the BLI.